I use GBL in large quantities on a daily basis and have done for the last coupla years but have never used 1,4B cos it's generally perceived as being greatly inferior to GBL/GHB and with far more unpleasant side-effects. 1,4B is pretty toxic stuff that will screw your liver and leave you with a vicious hangover, GBL/GHB is relatively non-toxic with no hangover for most. There are a handful of reports of 1,4B use in the GBL Megathread over in EADD (linky in my sig) but they are uniformly bad. Both are highly addictive but GBL is at least fun and doesn't screw your liver along the way. Used in moderation neither are probably all that bad but I wouldn't touch 1,4B with a ten foot pole myself. From what I've read the actual effects are fairly similar but 1,4B feels dirtier and has more of a "drunk" vibe to it than GBL.